1. Field of the Invention
The present invention relates to a backlight module, light guide plate thereof and ink thereof, and more particularly to an ink comprising a polymer having hydroxy functional group, ester functional group, ether functional group or combination thereof, and backlight module and light guide plate including the same.
2. Description of the Related Art
FIG. 1 shows a schematic view of a conventional backlight module. The backlight module 1 includes a light source 11, a reflector 12, a light guide plate 13 and a diffusion film 16. The light source 11, for example, a plurality of LEDs or CCFLs, is used to provide a light beam. The reflector 12 is disposed below the light guide plate 13, and is used to reflect part of the light beam back to the light guide plate 13.
The light guide plate 13 is used to receive and mix the light beam from the light source 11. The light guide plate 13 includes a light guide plate body 14 and an ink 15. The light guide plate body 14 has a first surface 141, a second surface 142 and a side surface 143. The first surface 141 is opposite the second surface 142, and the side surface 143 is adjacent to the first surface 141 and the second surface 142. The light source 11 faces the side surface 143, so that the light beam enters the light guide plate body 14 through the side surface 143 and is then transmitted to the diffusion film 16 through the second surface 142. The material of the light guide plate body 14 is transparent polymer, for example, polymethyl methacrylate (PMMA) or polycarbonate (PC).
The ink 15 is printed on the first surface 141 of the light guide plate body 14 to form a pattern, so as to reflect the light beam back to the interior of the light guide plate body 14. The ink 15 includes a base resin, a plurality of fillers and an additive. The material of the base resin is epoxy resin, polyester resin, acrylic resin, polyvinyl resin, polyamide resin or polyurethane resin. The fillers are fine particles that are dispersed in the base resin for diffusing light. The additive is dispersed in the base resin for increasing the printability of the ink 15.
Since the material of the fillers and the additive are inorganic, for example, silica, the backlight module 1 has drawbacks such as high color difference and high variation of color temperature. Usually, the color difference measured between points on the surface of a panel 17 above the diffusion film 16 is greater than 0.01. Such phenomenon will become more obvious when the optical path length of the light beam is longer.
Therefore, it is necessary to provide a light guide plate and ink thereof to solve the above problems.